(AP) Anti-death penalty forces have gained momentum in the past few years, with a moratorium in Illinois, court disputes over lethal injection in more than a half-dozen states and progress toward outright abolishment in New Jersey.

The steady drumbeat of DNA exonerations — pointing out flaws in the justice system — has weighed against capital punishment. The moral opposition is loud, too, echoed in Europe and the rest of the industrialized world, where all but a few countries banned executions years ago.

What gets little notice, however, is a series of academic studies over the last half-dozen years that claim to settle a once hotly debated argument — whether the death penalty acts as a deterrent to murder. The analyses say yes. They count between three and 18 lives that would be saved by the execution of each convicted killer.

The reports have horrified death penalty opponents and several scientists, who vigorously question the data and its implications.

So far, the studies have had little impact on public policy. New Jersey's commission on the death penalty this year dismissed the body of knowledge on deterrence as "inconclusive."

But the ferocious argument in academic circles could eventually spread to a wider audience, as it has in the past.

"Science does really draw a conclusion. It did. There is no question about it," said Naci Mocan, an economics professor at the University of Colorado at Denver. "The conclusion is there is a deterrent effect."

A 2003 study he co-authored, and a 2006 study that re-examined the data, found that each execution results in five fewer homicides, and commuting a death sentence means five more homicides. "The results are robust, they don't really go away," he said. "I oppose the death penalty. But my results show that the death penalty (deters) — what am I going to do, hide them?"

Statistical studies like his are among a dozen papers since 2001 that capital punishment has deterrent effects. They all explore the same basic theory — if the cost of something (be it the purchase of an apple or the act of killing someone) becomes too high, people will change their behavior (forego apples or shy away from murder).

To explore the question, they look at executions and homicides, by year and by state or county, trying to tease out the impact of the death penalty on homicides by accounting for other factors, such as unemployment data and per capita income, the probabilities of arrest and conviction, and more.

Among the conclusions: Each execution deters an average of 18 murders, according to a 2003 nationwide study by professors at Emory University. (Other studies have estimated the deterred murders per execution at three, five and 14). The Illinois moratorium on executions in 2000 led to 150 additional homicides over four years following, according to a 2006 study by professors at the University of Houston. Speeding up executions would strengthen the deterrent effect. For every 2.75 years cut from time spent on death row, one murder would be prevented, according to a 2004 study by an Emory University professor.

Not buying it. There's about 5 homicides in North Dakota a year. Does that mean if ND had the death penalty, it would have no homicides ever year it executed someone? Also by this standard we could have a murder-free year in Minnesota with about 10 executions.

Not buying it. There's about 5 homicides in North Dakota a year. Does that mean if ND had the death penalty, it would have no homicides ever year it executed someone?

Unlikely - murders deterred by the death penalty would more than likely be ones that are premeditated, meaning people who are in their 'right' state of mind and not a highly emotional one. I'd be willing to be that most of those 5 homicides a year are crimes of passion. Given that North Dakota's demographics are different from a highly populated state like New York or California, it's not exactly valid to apply how this would affect North Dakota to the policy of other states.

Not buying it. There's about 5 homicides in North Dakota a year. Does that mean if ND had the death penalty, it would have no homicides ever year it executed someone? Also by this standard we could have a murder-free year in Minnesota with about 10 executions.

Where did they come to these conclusions? Not questioning them, but it seems rather specific to be able to state exactly how many murders an execution deterred. I couldn't find much in the article relating to the actual studies other than simply stating the conclusions.

Dont buy it. Murders happen more in countries with the death penalty. That's just common knowledge.

As much as I'm skeptical, you're abandoning a scientific study in favor of correlation/causation fudging?

I'm just calling the study bullocks. Perhaps what I said means nothing as well because of outside factors. However, I dont think of places like Europe and Canada as being as murderous as say the U.S. That probably has nothing to do with capital punishment though.

Not buying it. There's about 5 homicides in North Dakota a year. Does that mean if ND had the death penalty, it would have no homicides ever year it executed someone? Also by this standard we could have a murder-free year in Minnesota with about 10 executions.

The article says this

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They count between three and 18 lives that would be saved by the execution of each convicted killer

The article makes no mention of timeframes, so your counter-argument is invalid. But it's not as bad as this guy's:

Dont buy it. Murders happen more in countries with the death penalty. That's just common knowledge. Plus, since when did Libertarians advocate for capital punishment?

Yeah well, there's also a correlation between shoe size and spelling ability. In fact, based on this result I'm going to have my little girl's feet surgically altered to be bigger, so that she can spell better.

Not buying it. There's about 5 homicides in North Dakota a year. Does that mean if ND had the death penalty, it would have no homicides ever year it executed someone? Also by this standard we could have a murder-free year in Minnesota with about 10 executions.

The article says this

Quote

They count between three and 18 lives that would be saved by the execution of each convicted killer

The article makes no mention of timeframes, so your counter-argument is invalid. But it's not as bad as this guy's:

Dont buy it. Murders happen more in countries with the death penalty. That's just common knowledge. Plus, since when did Libertarians advocate for capital punishment?

Yeah well, there's also a correlation between shoe size and spelling ability. In fact, based on this result I'm going to have my little girl's feet surgically altered to be bigger, so that she can spell better.

The real problem I have with the study is that the numbers are absurdly unrealistic. 10 murders prevented? I might be able to accept the idea that every two executions prevent one murder or some similarly modest number, but 10 murders for every execution not performed is absolutely absurd. That would suggest that states without the death penalty should have enormous murder rates--and that simply isn't the case; in fact, they tend to be below average.

It sounds like a pseudo-scientific study that found what it expected to find because it expected to find it.

The real problem I have with the study is that the numbers are absurdly unrealistic. 10 murders prevented? I might be able to accept the idea that every two executions prevent one murder or some similarly modest number, but 10 murders for every execution not performed is absolutely absurd. That would suggest that states without the death penalty should have enormous murder rates--and that simply isn't the case; in fact, they tend to be below average.

It sounds like a pseudo-scientific study that found what it expected to find because it expected to find it.

Correlation of variables A and B can mean three things:1) A causes B, 2) B causes A, or3) something causes both of them.

OK, so we have a correlation between high murder rates and executions for murder. Our options:1) high murder rate causes death penalty2) death penalty causes high murder rate3) something causes both the death penalty and the high murder rate

This study (once properly peer-reviewed and followed up on) basically says that option 2) is flat wrong. Indeed, if option 1) is the case then states without the death penalty won't have high murder rates (if they did, they'd have the death penalty).

That leaves option 3) as your only leg to stand on. But if the underlying cause to the death penalty is not present, then an underlying cause of high murder rates is not present. Again, you don't have a leg to stand on.

The real problem I have with the study is that the numbers are absurdly unrealistic. 10 murders prevented? I might be able to accept the idea that every two executions prevent one murder or some similarly modest number, but 10 murders for every execution not performed is absolutely absurd. That would suggest that states without the death penalty should have enormous murder rates--and that simply isn't the case; in fact, they tend to be below average.

It sounds like a pseudo-scientific study that found what it expected to find because it expected to find it.

Yeah. In Austria we have 60 homicides each year. The country has 8.3 Mio. inhabitants, which brings the homicide rate to 0.7 per 100.000, one of the lowest on the planet. We don´t have the death penalty.

The best thing we could do now in Austria with its 60 homicides, is to re-instate the death penalty, because if every execution prevents 10 homicides, we just execute the 60 murderers and we not just prevent 60 other homcides, but we also have a zero homicide rate and we would be the first country on the planet where potential killers give birth to 540 peace loving hippies by parthenogenesis.

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It sounds like a pseudo-scientific study that found what it expected to find because it expected to find it.

Yeah. These nuts should better create a study on the effect of poverty, violence and living standards in death-penalty or non-death-penalty areas. For example I say the death penalty has no detterent effect whatsoever on homicide rates.

Compare Germany/France and Colombia/South Africa. Both do not have the death penalty. Germany/France have homicide rates of 1-2/100.000 while Colombia/South Africa have rates of 50-80/100.000

Compare Singapore/South Korea/Japan (countries with DP) with Jamaica (with DP). While the first group has a homicide rate of 1-2/100.000, Jamaica has a rate of 40 homicides per 100.000

So what do Germany/France/Singapore/Japan/South Korea as well as Colombia/South Africa/Jamaica have in common ?

The 1. group has a functional social security net, more or less low unemployment and a peaceful society.

The second group of states experiences civil war, racism, high unemployment, high gunownership etc.

So, no matter how many studies are out there which show the DP prevents any murders, I will NEVER believe them, because the real problems of high homicide rates are a matter of poverty and misery.

The real problem I have with the study is that the numbers are absurdly unrealistic. 10 murders prevented? I might be able to accept the idea that every two executions prevent one murder or some similarly modest number, but 10 murders for every execution not performed is absolutely absurd. That would suggest that states without the death penalty should have enormous murder rates--and that simply isn't the case; in fact, they tend to be below average.

It sounds like a pseudo-scientific study that found what it expected to find because it expected to find it.

Correlation of variables A and B can mean three things:1) A causes B, 2) B causes A, or3) something causes both of them.

OK, so we have a correlation between high murder rates and executions for murder. Our options:1) high murder rate causes death penalty2) death penalty causes high murder rate3) something causes both the death penalty and the high murder rate

This study (once properly peer-reviewed and followed up on) basically says that option 2) is flat wrong. Indeed, if option 1) is the case then states without the death penalty won't have high murder rates (if they did, they'd have the death penalty).

One study doesn't convince me of anything, including that 1) is false (though I'm not inclined to say 1) is true, either). But let's refute your point anyway.

It would still make sense--if the standard argument against the death penalty in states without it were that there aren't enough murders to justify it. But that's not the case; it's usually argued on a humanitarian basis and occasionally on a financial basis but never on a "we don't need it" basis.

Consider how many executions happen per year in Texas. Do you really think that Texas would have had 3,900 more murders, including 120 more just so far this year, without the death penalty? That number is ridiculous!

Moreover, Texas used to execute peole on an average of 4 per year in the 1980s. Now it executes an average of 20 people per year, but its murder rate has gone up, not down. The study suggests that the murder rate should have dropped dramatically as the execution rate rose, but clearly this isn't the case. Option 3) is sounding better and better.

Quote

That leaves option 3) as your only leg to stand on. But if the underlying cause to the death penalty is not present, then an underlying cause of high murder rates is not present. Again, you don't have a leg to stand on.

If there's no causation involved, then this study is wrong, and clearly the death penalty does not deter murders. You just proved my point rather than disproving it.

Dont buy it. Murders happen more in countries with the death penalty. That's just common knowledge. Plus, since when did Libertarians advocate for capital punishment?

Who says Libertarians can't be for capital punishment? In my opinion it is a fitting punishment for certain crimes. You only have to read the paper to find examples of crimes which are so viscious and so horrible that they just scream out for the death penalty.

Where did they come to these conclusions? Not questioning them, but it seems rather specific to be able to state exactly how many murders an execution deterred. I couldn't find much in the article relating to the actual studies other than simply stating the conclusions.